[PATCH 2/2] libxfs: factor mount checks into helper function

[Eric Sandeen <sandeen@xxxxxxxxxxx>]

platform_check_ismounted switched to a getmntent() loop after
ustat disappeared on some new platforms.

We also use a similar mechanism for determining the
ro/rw-mounted status of a device in platform_check_iswritable.

Because the loops are essentially the same, factor them into a
single helper which accepts a VERBOSE flag to print info if the
device is found in the checked-for state, and a WRITABLE flag
which only checks specifically for a mounted and /writable/ device.

Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
---

V2: rebase, as the ustat-removal is already committed upstream.

diff --git a/libxfs/linux.c b/libxfs/linux.c
index 2b67d1a..30aa276 100644
--- a/libxfs/linux.c
+++ b/libxfs/linux.c
@@ -45,8 +45,15 @@ static int max_block_alignment;
 
 #define PROC_MOUNTED   "/proc/mounts"
 
-int
-platform_check_ismounted(char *name, char *block, struct stat64 *s, int 
verbose)
+/*
+ * Check if the filesystem is mounted.  Be verbose if asked, and
+ * optionally restrict check to /writable/ mounts (i.e. RO is OK)
+ */
+#define        CHECK_MOUNT_VERBOSE     0x1
+#define        CHECK_MOUNT_WRITABLE    0x2
+
+static int
+platform_check_mount(char *name, char *block, struct stat64 *s, int flags)
 {
        FILE            *f;
        struct stat64   st, mst;
@@ -54,6 +61,7 @@ platform_check_ismounted(char *name, char *block, struct 
stat64 *s, int verbose)
        char            mounts[MAXPATHLEN];
 
        if (!s) {
+               /* If either fails we are not mounted */
                if (stat64(block, &st) < 0)
                        return 0;
                if ((st.st_mode & S_IFMT) != S_IFBLK)
@@ -63,6 +71,7 @@ platform_check_ismounted(char *name, char *block, struct 
stat64 *s, int verbose)
 
        strcpy(mounts, (!access(PROC_MOUNTED, R_OK)) ? PROC_MOUNTED : MOUNTED);
        if ((f = setmntent(mounts, "r")) == NULL) {
+               /* Unexpected failure, warn unconditionally */
                fprintf(stderr,
                    _("%s: %s possibly contains a mounted filesystem\n"),
                    progname, name);
@@ -73,48 +82,49 @@ platform_check_ismounted(char *name, char *block, struct 
stat64 *s, int verbose)
                        continue;
                if (mst.st_dev != s->st_rdev)
                        continue;
+               /* Found our device, is RO OK? */
+               if ((flags & CHECK_MOUNT_WRITABLE) && hasmntopt(mnt, MNTOPT_RO))
+                       continue;
+               else
+                       break;
+       }
+       endmntent(f);
+
+       /* No mounts contained the condition we were looking for */
+       if (mnt == NULL)
+               return 0;
 
-               if (verbose)
+       if (flags & CHECK_MOUNT_VERBOSE) {
+               if (flags & CHECK_MOUNT_WRITABLE) {
                        fprintf(stderr,
-                               _("%s: %s contains a mounted filesystem\n"),
+_("%s: %s contains a mounted and writable filesystem\n"),
                                progname, name);
-               break;
-       }
-       endmntent(f);
-       return mnt != NULL;
+               } else {
+                       fprintf(stderr,
+_("%s: %s contains a mounted filesystem\n"),
+                               progname, name);
+               }
+       }
+       return 1;
 }
 
 int
-platform_check_iswritable(char *name, char *block, struct stat64 *s)
+platform_check_ismounted(char *name, char *block, struct stat64 *s, int 
verbose)
 {
-       FILE            *f;
-       struct stat64   mst;
-       struct mntent   *mnt;
-       char            mounts[MAXPATHLEN];
+       int flags;
 
-       strcpy(mounts, (!access(PROC_MOUNTED, R_OK)) ? PROC_MOUNTED : MOUNTED);
-       if ((f = setmntent(mounts, "r")) == NULL) {
-               fprintf(stderr, _("%s: %s contains a possibly writable, "
-                               "mounted filesystem\n"), progname, name);
-                       return 1;
-       }
-       while ((mnt = getmntent(f)) != NULL) {
-               if (stat64(mnt->mnt_fsname, &mst) < 0)
-                       continue;
-               if ((mst.st_mode & S_IFMT) != S_IFBLK)
-                       continue;
-               if (mst.st_rdev == s->st_rdev
-                   && hasmntopt(mnt, MNTOPT_RO) != NULL)
-                       break;
-       }
-       endmntent(f);
+       flags = verbose ? CHECK_MOUNT_VERBOSE : 0;
+       return platform_check_mount(name, block, s, flags);
+}
 
-       if (mnt == NULL) {
-               fprintf(stderr, _("%s: %s contains a mounted and writable "
-                               "filesystem\n"), progname, name);
-               return 1;
-       }
-       return 0;
+int
+platform_check_iswritable(char *name, char *block, struct stat64 *s)
+{
+       int flags;
+
+       /* Writable checks are always verbose */
+       flags = CHECK_MOUNT_WRITABLE | CHECK_MOUNT_VERBOSE;
+       return platform_check_mount(name, block, s, flags);
 }
 
 int